Just a week after losing her leading Golden Slipper hope to injury, Gai Waterhouse has produced another contender at Randwick.

The racing future of the Waterhouse-trained Fighting Sun is in doubt with the colt was found to have an injury after his win a week ago which elevated him to second favourite for the Slipper.

Valentia, a $1.35 million colt and the sale topper at the 2013 Magic Millions sale, showed the benefit of his debut third behind Rubick to win Saturday's 1200m event for two-year-olds.

Tommy Berry brought Valentia ($4.20) along the rail inside race leader Greco ($8) to beat his rival by a neck.

Colm Santry, representing owners Coolmore, said the colt was in the $3.5 million Golden Slipper on April 5 but he thought he might be better suited to the longer distances of the Sires' Produce Stakes and the Champagne Stakes.

"He is an expensive colt and very well bred by Fastnet Rock out of a Mister C mare so he will get over ground," Santry said.

But Waterhouse's right-hand man Mark Newnham said the Slipper was firmly on the agenda.

"He is in definitely in the Slipper," Newnham said.

"He's made good improvement from his first run. He blew the start last time but jumped well today."

Berry, who had staked his claim to ride Fighting Sun in the Slipper, agreed Valentia was an improving type.

"The tempo enabled me to travel in a stronger position," he said.

"He can get a bit lost so it was good to be where I was on the rail."

Race favourite Double Happy ($2.70) maintained his position throughout the race to finish fourth.